ES3217 Loss of Childhood

Semester 1, 2011.

On Evolution:

Some foundational ideas.

Based on the work of Umberto Maturana and Francisco Varela – see their 1998 publication, The Tree of Knowledge: the biological roots of human understanding, revised edtn., published in London by Shambhala. (But this in turn, is influenced by E. O Wilson’s text, Sociobiology: the new synthesis.)

Evolution is a natural process that occurs in all living things. As normally used, the term applies to populations, so that the characteristics of a population are said to ‘evolve’ over a period of time.

However, populations are made up of individuals, and the processes of change that the theory of evolution explains exist, in their immediate forms, as changes occurring to individuals. However, these individuals are always members of a population, however small and isolated it may be.

All living things are ‘autopoietic’. This means that they are self-determining – life itself consists of processes that have evolved to conserve the continuation of these same processes.

Every living thing conducts its own form of autopoiesis in an environment, but this is not easy. Because of the complexity and improbability of its life processes, relative to the characteristics of most environments; the living unity separates itself off from its environment. Individual cells have membranes, trees have their protective outer bark, insects have a hard and waxy exoskeleton, and animals have skins.

Few, if any, living things can survive indefinitely without having some form of interaction with the external world. There are certain basic functions that all living things must carry out which involve specialised forms of transaction with the world beyond their defensive ‘boundaries’.

These transactions are controlled by the internal structure and processes of the organism, and are mediated by the boundary. The most basic interactions of all are those which allow energy to enter the life-form from the external world, and internally produced waste to be returned to it.

But beyond this level of functionality, there is the need for self-repair and maintenance, since the life-form will die if it can no longer continue extracting energy from its environment and ejecting products that it can no longer metabolise (and which may, in fact, damage it if they are not removed).

At one higher level of functionality, there are processes which allow growth to occur, and beyond that, those specialised processes needed to ensure successful reproduction.

The last two may seem less immediately essential than the others, but from the perspective of population survival, they are.

Many of the processes constituting life occur at very small scales, and at such scales chemical and physical properties of things, in terms of their interactive potential, are greatly enhanced. At any organisational level, growth increases the capacity to withstand environmental perturbations. But beyond a certain point, these advantages are reversed. Some organisms respond to the problem by ‘budding’ – they reproduce ‘vegetatively’.

The majority of organisms, however, reproduce ‘sexually’. This involves the production of two different types of progenitor cells or spores that are classified as being either ‘male’ or ‘female’. This distinction rests on the unequal access the two types of reproductive units have to nutrients which will allow the new individual to achieve sufficient growth to be able to sustain an independent life. The female units either carry a stored supply of nutrients with them, or they are static and located where there is a ready supply of nutrients that the growing embryo can use.

Vegetative reproduction results in a single individual becoming multiple; all of the buds share the same characteristics as the original ‘adult’. However, each bud may experience a different life history as it attempts to survive – perhaps they are carried far away by an ocean current rather than lodging on top of their ‘parent’. These different outcomes may result in changes to the characteristics of the unit and this may be transmitted to succeeding generations. But when one talks of a population in this case, the assumption is that although reductive specialisation may be possible, the development of completely new characteristics is less likely.

Sexual reproduction, on the other hand, produces unique individuals that are assumed to share an equal but random mixture of characteristics from the male and female parents. (Technically, the frequency of gene alleles changes, and sometimes a gene’s chromosome location also shifts.) The latter case may lead to the expression of characteristics never existing before. Darwin called these ‘sports’: today we call them ‘mutations’.

At this point, it becomes possible to talk meaningfully about evolution, because with growth and reproduction comes the capacity for populations to ‘move’ through time and space.

Autopoiesis exists with respect to individual cells, but cells can combine to form multicellular types, such as animals, plants, and fungi.

Each multicellular type survives by conducting its interactions with the environment at two functional levels: at a cellular level, through the provision and maintenance of an internal environment, e.g. a blood supply, and at a multicellular level through the provision of ‘survival’ features such as arms, claws, leaves, and roots, etc.

In both first and second order autopoiesis, the units are self-determining, but in the case of individual cells within a multicellular unity, its specialised life processes are triggered by signals from its internal environment, which may be almost entirely constituted by other cells. The individual cells of multicellular types are said to be ‘coupled’ to certain features of their specific intracellular environment that are recurrent, and their responses to these signals are said to be reciprocal. Their specialisation and second order functionality is a consequence of the cells of multicellulars having become ‘adapted’.

Adaptation is the key to understanding evolution, and autopoiesis the key to understanding adaptation. The autopoiesis of an organism entails that its structure and processes are such as to maintain life through a capacity to utilise regular ‘perturbations’ occurring in its environment, e.g. a temperature range, a tidal range, a regular growth or migration cycle, etc. Its structures and processes are said to be ‘adapted’ to these aspects of its environment. Two things follow: other aspects of the environment are ignored or avoided; and if it survives, its own life processes may change these critical aspects of its environment, creating an evolutionary ‘niche’.

How has this happened? As we have seen, unitary survival rests on a capacity to establish reciprocal relationships between a unity’s internal processes and structures, and selected characteristics of its environment. What has been left out of the explanation so far is the notion that the characteristics of a unity, including its capacity to form such coupling relationships, are conserved from one generation to the next. This entails that if there is variation in the accuracy of conservation, differential survival will result and the population will become better adapted to specific features of its environment.

At this point it is helpful to picture how such adaptations might evolve within a population, and how the changes might lead to the creation of a new species.

The starting point is to assume that each individual in a population has a chance to reach maturity and survive long enough to ensure the survival of its progeny. If the chance of doing this is low, the species may die out, and if the chance is high, the population may exhaust its food supplies and its numbers will collapse until such time as improved food supplies become available.

Suppose that a chance mutation results in a few grazing animals in a population having more efficient grinding teeth than is the norm. If food is not abundant at the time they reach maturity, those individual are likely to have an increased chance of reproductive success, and the next generation of the population will exhibit an increased frequency of better grinding teeth. If the relative lack of food persists, the survival value of the mutation is such that it is likely that these more efficient grinding teeth will come to be the norm for that population.

Now consider a different case. If a small group of individuals with the improved teeth becomes isolated from the main population, and the difficult feeding condition become even worse, then the resulting ‘island’ population is likely to exhibit more rapid evolution. But what will change will not simply be the new teeth design: living unities are not just collections of characteristics. Instead they integrate features, processes, and behaviour to build complex inter-relationships with their environments. If the isolated group rejoins the original population, changes such as these will, ultimately, result in the two groups becoming incapable of inter-breeding.

In this way new species are formed, but, equally, a failure to adapt will eventually result in a species becoming extinct.

We now get to the principal focus of this module. Just as there is autopoiesis at the level of the cell, and autopoiesis at the level of the multicellular organism, so there is a third level of autopoiesis at the level of the social group. Consider herd and pack animals - each type has evolved distinct ways of surviving as groups. As individuals, their survival potential is much reduced if they are isolated. This is clearly the case in our own species, but does language and culture make a difference?

Maturana and Varela’s work has been chosen to start this level six module because it is non-technical in its explanations. Next week we move onto a more detailed analysis of the social, with the help of E. O. Wilson’s now famous text, Sociobiology: the new synthesis. The following is taken from the start of his second chapter, and for those of you who either have read one or more of Richard Dawkins’ books, or are prepared to try one now, you will immediately recognise the similarity in perspective; in fact, it is now the common view in biology.

Genes, like Leibniz’s monads, have no windows; the higher properties of life are emergent. To specify an entire cell, we are compelled to provide not only the nucleotide sequences but also the identity and configuration of other kinds of molecules placed in and around the cell. To specify an organism requires still more information about both the properties of the cells and their spatial positions. And once assembled, organisms have no windows. A society can be described only as a set of particular organisms, and even then it is difficult to extrapolate the joint activity of this ensemble from the instant of specification, that is, to predict social behaviour. … The recognition and study of emergent properties is holism, once a burning subject for philosophical discussion … .

Wilson, p. 7.